As an upstart Manhattan-based gossip site with a reputation for iconoclasm and baiting celebrities, Gawker.com has always been clear in its priorities: attract traffic, make money, don't fret too much about upsetting your subjects.

But the agent provocateur of the New York media scene appeared to have crossed one line too many, after it published a prurient kiss and tell about the Republican senatorial candidate and Tea Party darling Christine O'Donnell.

O'Donnell has faced embarrassing revelations before in her campaign to be elected senator for Delaware in next Tuesday's US midterms – most notoriously, she was revealed to have dabbled in witchcraft as a young woman, forcing her to issue a TV ad that opens: "I am not a witch ...". She admitted campaigning against masturbation during the 1990s and her knowledge of the US constitution was embarrassingly exposed during a campaign meeting.

Gawker's revelation that she had spent a drunken night with an unnamed man three years ago, however – detailing in the most ungentlemanly of terms her appearance "when her underwear came off" – appeared to have achieved the most unlikely feat of her campaign so far: sparking indignation among the mainstream media and winning her defenders from the left as well as the right.

"Gawker Hits O'Donnell While She's Down", read a blog at TheAtlantic.com (O'Donnell is 21 points behind her Democrat rival in the senatorial race), while Walter Shapiro at PoliticsDaily.com wrote: "What Gawker has achieved is something that I never thought possible. It made me feel sorry for Christine O'Donnell."

"I hate to be the person to defend her, but as feminists we have to defend all women from this nonsense, even women who are antifeminist," Jessica Valenti, the founder of feministing.com, told the Guardian.

Even the National Organisation for Women, the largest feminist organisation in the US, hit out at the "slut-shaming" approach of the article. "NOW repudiates Gawker's decision to run this piece," said NOW's president Terry O'Neill. "It operates as public sexual harassment. And like all sexual harassment, it targets not only O'Donnell, but all women contemplating stepping into the public sphere."

The piece, entitled I Had a One Night Stand with Christine O'Donnell, was published on the site on Thursday, and concerned the events of an evening three years ago, when the author claimed O'Donnell, an acquaintance, had turned up at his home in Philadelphia and asked if she could change into her Halloween outfit – a ladybird. After persuading the unnamed author and his flatmate to accompany her for drinks, O'Donnell had reportedly stayed the night in the man's bed, though they had not had sex. (The man has since, perhaps inevitably, been named by a number of websites).

From Gawker's point of view, this story was not unusual — three weeks ago, it published an article about Democrat congressional candidate Krystal Ball entitled 9 Pictures of a Politician Sucking a Dildo Attached to a Man's Nose. The O'Donnell piece, accordingly, seems to have caused Nick Denton, Gawker Media's British founder, little concern. In a memo to staff on Thursday, he congratulated them on "an example of brilliant packaging".

Remy Stern, the site's editor, told the Guardian: "It was a compelling story and we stand by it. It speaks to a certain hypocrisy given her views on sexuality."

But for some of those close to the organisation, there was no question that Gawker's "anything goes" culture of mischief-making had finally gone too far. "It definitely feels off," said Chiore Sicha, a former editor of the site who now co-edits TheAwl.com. "This is Gawker not quite getting its mission right. I have talked to Nick about it."

By publishing a story by "some enormous schmoe" in which O'Donnell had not behaved particularly embarrassingly – "for most people this is just your average Halloween" – the site had badly misjudged its audience, said Sicha. But as for the site's founder: "Nick is never one to worry about what people are saying. He doesn't really care."

Other media watchers agree that Denton, who pays his staff partly based on the traffic their stories generate, will lose no sleep over the media brouhaha.

"Nick has a travelling carnival moving at high speed, and he will be delighted by this," said Jack Shafer, the respected media columnist at Slate.com. Neither the kiss and tell form nor the prurience of the story was particularly new, he said, even in American political discourse. "It's the volume at which Nick Denton is playing this story that is new." Denton's talent, he said, was as a "shape-shifter", appealing to journalistic mores when it suited him, side-stepping its ethics when it did not.

And the giddy ringmaster certainly appears to have achieved his aim. By last night a story titled Katy Perry Shoots More Stuff Out of Her Boobs, also posted on Thursday, had garnered 10,660 page views. The O'Donnell kiss and tell was ranking at 720,680. And, as Shafer noted: "Everyone who complained about it has read to the end."

Other Gawker controversies

Tom Cruise Scientology video

The Church of Scientology forced several websites to take down a video of Tom Cruise extolling the virtues of Scientology. But one site refused to give in – Gawker, who claimed that they could continue to host the video because it was "newsworthy". The video remains on their website.

Grey's Anatomy "sex tape"

In 2009, Gawker were sued for $1m by Grey's Anatomy star Eric Dane for streaming a video depicting him, his actor wife Rebecca Gayheart, and former Miss Teen USA Kari Ann Peniche frolicking naked in a jacuzzi. Gawker removed the video this July after a settlement was reached.

Gawker Stalker

First introduced in 2006, Gawker Stalker invites readers to email their photos and reports of celebrity sightings in New York. The location of each sighting is then tagged on a Google map of the city. Celebrities complain that it makes them more vulnerable to attack. George Clooney's spokesman Steve Rosenfield said: "Someone could get hurt over it. You don't know who's reading it."

Dispute with Apple

Gawker writer Ryan Tate was embroiled in a leaked email argument with Steve Jobs from Apple – which began with Tate questioning Jobs's desire to give the iPad "freedom from porn", and ended with Jobs asking: "What have you done that's so great?"